Perhaps you should try some spelling variations:
tham thuc » nham thuc, tam thuc, thai thuc
sach tham » sach nha
pham thuc » phap thuc, pham chuc, nham thuc
hanh via » hanh vi, hanh va, anh va
via cua » gia cua, gian cua, giau cua
va hanh » van hanh, va thanh, va danh
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ty) or (sach tham)) lang xa hoi. hieu ve ((tham thuc) or (pham thuc)) va hanh via cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach tham)) lang xa hoi. hieu ve ((tham thuc) OR (pham thuc)) va hanh via cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach tham)) lang xa hoi. hieu ve ((tham thuc) or (pham thuc)) va hanh via cua tre*.